Auxiliary Verbs

Auxiliary, or helping, verbs are among the most vital elements of English grammar. They work together with the main verb in a sentence to give a certain voice, mood, tense, or aspect. Auxiliary verbs offer us more control over our language, enabling us to add more detail or depth than if we just had the main verb alone.

What are Auxiliary Verbs?

Auxiliary verbs, often known as “helping verbs,” are verbs that help to give additional meaning to the main verb in a clause. They are used to express tense, voice, mood, aspect, emphasis, and more. There are three types of auxiliary verbs in English: 'be', 'have' and 'do'.

Be, Have, Do

These are the primary auxiliary verbs or helper verbs. They can either function as main verbs or auxiliary verbs depending on their usage.

  • Be: The auxiliary verb 'be' is used in continuous tenses and passive voice sentences. For instance, 'I am reading a book.' Here, 'am' is the auxiliary verb that supports the main verb 'reading'.
  • Have: 'Have' is used in perfect tenses. For example, 'I have written a letter.' In this sentence, 'have' is the auxiliary verb that supports the main verb 'written'.
  • Do: 'Do' is used in simple present and past tenses. This auxiliary verb is also often used for questions, negative statements, negative imperatives and emphasising positive statements. For example, in the sentence 'Do you have a pen?', 'do' is the auxiliary verb.

Modal Auxiliary Verbs

Modal auxiliary verbs are another type of helping verb. They are used to express necessity, possibility, prediction or permission. The modal auxiliary verbs include: can, could, may, might, will, would, shall, should, must.

  • Can: Used for abilities. For instance, 'I can swim.'
  • Could: Used for possibilities. 'You could be right.'
  • May: Used for permissions. 'You may go now.'
  • Might: Used to indicate a small probability. 'It might rain today.'
  • Will: Used for predictions. 'She will come tomorrow.'
  • Would: Used for assumptions. 'They would know.'
  • Shall: Used for future actions. 'I shall leave now.'
  • Should: Used for obligations. 'You should apologize.'
  • Must: Used for necessities. 'He must go home.'

Rules for Using Auxiliary Verbs

Just as important as knowing what auxiliary verbs are, is knowing how to use them correctly. Here are some important rules for using these verbs correctly in your writing and speech.

Continuous Tenses

In continuous tenses, we use the auxiliary verb ‘be’ (am/is/are in present, was/were in the past) and follow it with the verb + ing.

  • 'They are playing football.'
  • 'I was preparing dinner.'

Perfect Tenses

In perfect tenses, we use the auxiliary verb 'have' (has/have in the present, had in the past) and follow with the past participle of the main verb.

  • 'She has finished her homework.'
  • 'They had left by then.'

Using 'Do'

We often use 'do', 'does' and 'did' when making questions in the present simple and past simple tenses, and when making negative statements.

  • 'Do you like chocolate?'
  • 'She does not admit her mistake.'

Modal Rules

Modal auxiliaries always appear before the main verb.

  • 'She must reconsider her decision.'

Unlike other auxiliary verbs, modals only exist in their helping form; they cannot stand alone as the main verb in a sentence. And unlike other verbs, modals do not change form according to tense.

Negative Forms

Auxiliary verbs are often used to form negative sentences with 'not'. When forming negative sentences, 'not' typically comes right after the auxiliary verb.

  • 'I am not eating.'
  • 'He does not play.'
  • 'They cannot come.'


Auxiliary verbs may seem small, but they carry a lot of weight when it comes to the tone and clarity of a statement. They offer additional information about the timing and mood of an action and can change the entire intent of a message. Knowing how to use them effectively in your writing and speech can make a big difference in your command of the English language.

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